The simple answer is yes, katakana is different from kanji. The longer answer is written Japanese uses kanji, katakana, hiragana, and romaji, as follows:
- Kanji; these are the characters derived from Chinese characters that Japanese use for verb stems, adjectives, nouns, etc.
- Hiragana; these are syllabaries (46 characters, each representing a phonic) used for verb endings (such as past, present, and future tenses), conjugation, etc.
- Katakana; these are also syllabaries (actually 46 simplified forms of the corresponding hiragana character) used to write foreign nouns, both for objects and people names.
- Romaji; these are the alphabet characters, generally restricted to advertising use and acronyms.